Beevers has been instrumental in the Lions' recent unbeaten run since arriving on loan and has not lost a game during his time in South London.

And, after the deal was confirmed on Thurdsay, Beevers told the club's official site: "I'm delighted to be joining Millwall in January. Things have gone very well for me here during my loan spell here.

He added: "The lads have made me very welcome, as have the fans and I'm looking forward to the next three years."